1. Technical Field
The present invention relates to a digital broadcasting service, and more particularly to a channel changing method when using a digital broadcasting service.
2. Related Art
Broadcasting on demand (BOD) is an example of a digital broadcasting service. The broadcasting on demand (BOD) currently represented by video on demand (VOD) is a service that provides in real time video information requested by a user. The broadcasting on demand (BOD) is not a unidirectional service that one-sidedly receives programs of the existing public network broadcasts or through a cable television (TV), but is a bi-directional service that can use desired contents at a desired time according to a subscriber's request. An infrastructure for providing the broadcasting on demand (BOD) requires a state in which a video database has been constructed, and the database has been connected to a home (or personal portable terminal) through a wideband transmission path (that is, cable or wireless path).
A set top box can be referred to as an interface unit, a set top box unit, a home user terminal, a home terminal, and other terms. The set top box can correspond to a device able to perform various functions. For example, a set top box can support Internet access through a television, and can provide users with high-speed access to the Internet via a cable modem or broadband network rather than the traditional telephone network plain old telephone services (POTS). In addition, a set top box can provide video-conferencing capabilities, can support community networking, and can provide media-on-demand (MOD) capabilities including video-on-demand, music-on-demand, news-on-demand, impulse-pay-per-view, and television-programs-on-demand. A set top box is often located at a remote user location enabling the user to transmit information signals such as requests, instructions, or other data. A set top box can include a central processing unit.
In order for a set top box unit (STU) to be provided with a broadcasting on demand (BOD) service and to select a channel from multiple video channels, a standard for defining a control message between a network and a subscriber's device is required. Such a standard is digital storage media-command and control (DSM-CC) defined in 13818-6 originated from International Standards Organization/International Electrotechnical Commission (ISO/IEC). The digital storage media-command and control (DSM-CC) has been designed to support services of video on demand (VOD) and other services in an asynchronous transfer mode (ATM) network. The digital storage media-command and control (DSM-CC) transmits broadcasting programs only to a replication unit and broadcast control unit (RU/BCU) in a transfer network such as a hybrid fiber coax (HFC) or fiber to the curb (FTTC), and the replication unit and broadcast control unit (RU/BCU) multicasts the broadcasting programs to the set top box unit.
The replication unit and broadcast control unit (RU/BCU) is different from a zapper server. A zapper server can be referred to as a channel change protocol (CCP) server. All broadcasting programs are transferred up to the channel change protocol (CCP) server, but are not transferred up to the set top box unit.
The digital storage media-command and control (DSM-CC) is classified into a session control protocol and a channel change protocol for controlling channel change after service connection. The session control protocol and the channel change protocol operate on different protocol stacks.
In the digital storage media-command and control (DSM-CC), the session control protocol is defined based on a transmission control protocol/Internet protocol (TCP/IP) protocol, and the channel change protocol is defined based on an AAL5/ATM protocol. ATM is asynchronous transfer mode. AAL5 is asynchronous transfer mode adaption layer 5.
According to the digital storage media-command and control (DSM-CC) standard, in a case where the service environment can support the asynchronous transfer mode (ATM), the technical implementation of digital storage media-command and control (DSM-CC) is possible. But in a case where the service environment cannot support the asynchronous transfer mode (ATM), and can only support the transmission control protocol/Internet protocol (TCP/IP), the technical implementation of the digital storage media-command and control (DSM-CC) is difficult.
Since the session control protocol and the channel change protocol should be implemented on the different protocol stacks, an additional manipulation or conversion is required in order to have compatibility between those two protocols. A message that is transmitted through the channel change protocol must be received at a first destination and then manipulated or converted, so that the contents of that message can then be transmitted to a second destination through the session control protocol.
The repeated changing of TCP/IP packets to ATM packets, and the repeated changing of ATM packets to TCP/IP packets would be necessary in that arrangement. The set top box unit that is the subject of requesting of the channel change, for the most part, has no asynchronous transfer mode (ATM) adaptation layer (AAL) mounted thereon, and it is necessary to develop a modified technique.
The digital storage media-command and control (DSM-CC) standard defines a session resource manager (SRM) that is a terminating set between the server and the set top box unit. The session resource manager (SRM) converts messages that are transmitted through the session control protocol to become messages to be transmitted through the channel change protocol. The session resource manager (SRM) converts messages that are transmitted through the channel change protocol to become messages to be transmitted through the session control protocol. The channel change protocol and the session control protocol operate on different protocol stacks.
If the digital storage media-command and control (DSM-CC) standard is applied without modification, it causes inconvenience and inefficiency such as putting the session onto the Internet protocol (IP), the sending of the channel on the asynchronous transfer mode adaption layer 5 and then on the Internet protocol network in a network interface unit (NIU), and the sending of a confirmation message in reverse order.
It is my observation that there is currently a lack of convenient and efficient methods supporting channel changing in digital broadcasting services. Efforts have been made to improve features related to networking and broadcasting services.
Exemplars of recent efforts related to networking and broadcasting services are disclosed, for example, in U.S. Pat. No. 5,550,578 to Hoarty et al., entitled INTERACTIVE AND CONVENTIONAL TELEVISION INFORMATION SYSTEM, issued on Aug. 27, 1996, U.S. Pat. No. 5,805,591 to Naboulsi et al., entitled SUBSCRIBER NETWORK INTERFACE, issued on Sep. 8, 1998, U.S. Pat. No. 6,219,355 to Brodigan, entitled VIDEO AND DATA COMMUNICATION SYSTEM, issued on Apr. 17, 2001, U.S. Pat. No. 5,734,589 to Kostreski et al., entitled DIGITAL ENTERTAINMENT TERMINAL WITH CHANNEL MAPPING, issued on Mar. 31, 1998, U.S. Pat. No. 6,317,884 to Eames et al., entitled VIDEO, DATA AND TELEPHONY GATEWAY, issued on Nov. 13, 2001, and U.S. Pat. No. 6,473,427 to Brodigan, entitled ATM BASED VDSL COMMUNICATION SYSTEM HAVING META SIGNALING FOR SWITCHING A SUBSCRIBER BETWEEN DIFFERENT DATA SERVICE PROVIDERS, issued on Oct. 29, 2002.
While these contemporary efforts contain merit, it is my observation that further improvements can be contemplated.